1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * R-Car Generation 2 da9063/da9210 regulator quirk
4  *
5  * Certain Gen2 development boards have an da9063 and one or more da9210
6  * regulators. All of these regulators have their interrupt request lines
7  * tied to the same interrupt pin (IRQ2) on the SoC.
8  *
9  * After cold boot or da9063-induced restart, both the da9063 and da9210 seem
10  * to assert their interrupt request lines.  Hence as soon as one driver
11  * requests this irq, it gets stuck in an interrupt storm, as it only manages
12  * to deassert its own interrupt request line, and the other driver hasn't
13  * installed an interrupt handler yet.
14  *
15  * To handle this, install a quirk that masks the interrupts in both the
16  * da9063 and da9210.  This quirk has to run after the i2c master driver has
17  * been initialized, but before the i2c slave drivers are initialized.
18  *
19  * Copyright (C) 2015 Glider bvba
20  */
21 
22 #include <linux/device.h>
23 #include <linux/i2c.h>
24 #include <linux/init.h>
25 #include <linux/io.h>
26 #include <linux/notifier.h>
27 #include <linux/of.h>
28 #include <linux/mfd/da9063/registers.h>
29 
30 
31 #define IRQC_BASE		0xe61c0000
32 #define IRQC_MONITOR		0x104	/* IRQn Signal Level Monitor Register */
33 
34 #define REGULATOR_IRQ_MASK	BIT(2)	/* IRQ2, active low */
35 
36 /* start of DA9210 System Control and Event Registers */
37 #define DA9210_REG_MASK_A		0x54
38 
39 static void __iomem *irqc;
40 
41 /* first byte sets the memory pointer, following are consecutive reg values */
42 static u8 da9063_irq_clr[] = { DA9063_REG_IRQ_MASK_A, 0xff, 0xff, 0xff, 0xff };
43 static u8 da9210_irq_clr[] = { DA9210_REG_MASK_A, 0xff, 0xff };
44 
45 static struct i2c_msg da9xxx_msgs[3] = {
46 	{
47 		.addr = 0x58,
48 		.len = ARRAY_SIZE(da9063_irq_clr),
49 		.buf = da9063_irq_clr,
50 	}, {
51 		.addr = 0x68,
52 		.len = ARRAY_SIZE(da9210_irq_clr),
53 		.buf = da9210_irq_clr,
54 	}, {
55 		.addr = 0x70,
56 		.len = ARRAY_SIZE(da9210_irq_clr),
57 		.buf = da9210_irq_clr,
58 	},
59 };
60 
61 static int regulator_quirk_notify(struct notifier_block *nb,
62 				  unsigned long action, void *data)
63 {
64 	struct device *dev = data;
65 	struct i2c_client *client;
66 	static bool done;
67 	u32 mon;
68 
69 	if (done)
70 		return 0;
71 
72 	mon = ioread32(irqc + IRQC_MONITOR);
73 	dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
74 	if (mon & REGULATOR_IRQ_MASK)
75 		goto remove;
76 
77 	if (action != BUS_NOTIFY_ADD_DEVICE || dev->type == &i2c_adapter_type)
78 		return 0;
79 
80 	client = to_i2c_client(dev);
81 	dev_dbg(dev, "Detected %s\n", client->name);
82 
83 	if ((client->addr == 0x58 && !strcmp(client->name, "da9063")) ||
84 	    (client->addr == 0x68 && !strcmp(client->name, "da9210")) ||
85 	    (client->addr == 0x70 && !strcmp(client->name, "da9210"))) {
86 		int ret, len;
87 
88 		/* There are two DA9210 on Stout, one on the other boards. */
89 		len = of_machine_is_compatible("renesas,stout") ? 3 : 2;
90 
91 		dev_info(&client->dev, "clearing da9063/da9210 interrupts\n");
92 		ret = i2c_transfer(client->adapter, da9xxx_msgs, len);
93 		if (ret != len)
94 			dev_err(&client->dev, "i2c error %d\n", ret);
95 	}
96 
97 	mon = ioread32(irqc + IRQC_MONITOR);
98 	if (mon & REGULATOR_IRQ_MASK)
99 		goto remove;
100 
101 	return 0;
102 
103 remove:
104 	dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
105 
106 	done = true;
107 	iounmap(irqc);
108 	return 0;
109 }
110 
111 static struct notifier_block regulator_quirk_nb = {
112 	.notifier_call = regulator_quirk_notify
113 };
114 
115 static int __init rcar_gen2_regulator_quirk(void)
116 {
117 	u32 mon;
118 
119 	if (!of_machine_is_compatible("renesas,koelsch") &&
120 	    !of_machine_is_compatible("renesas,lager") &&
121 	    !of_machine_is_compatible("renesas,stout") &&
122 	    !of_machine_is_compatible("renesas,gose"))
123 		return -ENODEV;
124 
125 	irqc = ioremap(IRQC_BASE, PAGE_SIZE);
126 	if (!irqc)
127 		return -ENOMEM;
128 
129 	mon = ioread32(irqc + IRQC_MONITOR);
130 	if (mon & REGULATOR_IRQ_MASK) {
131 		pr_debug("%s: IRQ2 is not asserted, not installing quirk\n",
132 			 __func__);
133 		iounmap(irqc);
134 		return 0;
135 	}
136 
137 	pr_info("IRQ2 is asserted, installing da9063/da9210 regulator quirk\n");
138 
139 	bus_register_notifier(&i2c_bus_type, &regulator_quirk_nb);
140 	return 0;
141 }
142 
143 arch_initcall(rcar_gen2_regulator_quirk);
144